[MERGE] [3.1] Clean up commReset use in combination with tproxy or tcp_outgoing_address

Take two.

The change is that this version also tries to skip IPv4 addresses if the
socket is IPv6-only. This case should have been handled by existing code
paths, but the way that was done was quite twisted and apparently broke
down by my changes to commResetFD.

This patch backs out part of the patch for Bug #2222 and replaces it by
crudely cycling over the available addresses, trying to skip over
addresses not compatible with the current socket.

This solves issues seen when using tproxy or tcp_outgoing_address and
DNS of the requested host returns AAAA records in addition to A records.

This change is interim, waiting for the larger connection setup
overhaul. But seems to do the trick at least for me in tproxy & ipv4
setups. Unfortunately I do not have an IPv6 connection at the moment to
test IPv6 on, but I don't see how it could break IPv6.

One effect of this change is that there will be no fallback to the other
IP generation if the socket is configured to a specific outgoing
address. Priory the code threw away the outgoing address and tried
again when encountering an incompatibility.

Regards
Henrik